I teach a course (hopefully to be a book in the not-too-distant future)
which is about using Ajax for good (better user experience) rather than
evil (just making things more interactive for the sake of it).
One of my biggest frustrations/disappointments is to see Ajax applied
gratuitously to a page (to make the shopping basket more interesting,
for example) while inherent usability problems - like having to click
the 'Update' link if quantities are changed - remain unaddressed.
Anyway, this is a perennial problem in design that is not going to go
away any time soon.